Abstract: This research deals with the effects of different fillers of styrene butadiene rubber/recycled chloroprene rubber/carbon black (SBR/CRr/CB) blends and styrene butadiene rubber/recycled chloroprene rubber/calcium carbonate (SBR/CRr/CaCO3) blends on mechanical and morphological properties. The range size of CRr used in this study was 181 – 549 μm. Both SBR/CRr/CB blends and SBR/CRr/CaCO3 were prepared using a two roll mill at room temperature with blend ratios 95/5, 85/15, 75/25, 65/35 and 50/50. It can be observed that, tensile strength, Eb and rebound resilience of SBR/CRr/CB blends and SBR/CRr/CaCO3 blends decreased with increasing CRr content in both blends. However, M100 increased with increasing CRr content in both blends. The scanning electron microscopy (SEM) of the tensile fractured surface of SBR/CRr/CB blends illustrates better adhesion between CB and SBR matrix compared to SBR/CRr/CaCO3 blends at all blend ratios.Keywords: styrene butadiene rubber, recycled chloroprene rubber, mechanical properties, SEM
Abstract: Polyurethane (PU)/multiwalled carbon nanotubes (MWCNTs) foam composites were produced by reaction of based palm oil polyol (POP) with methylene diphenyl diisocyanate (MDI). The MWCNTs were added into PU foam with the percentages varied from 0 wt.% to 3 wt.%. Sandwich composites were prepared using hand lay-up method where Aluminium (Al) sheet as skin were stacked onto PU foam using Araldite adhesives. The PU/MWCNTs foam composites (PMFC) and PU/MWCNTs foam sandwich composites (PMFSC) were characterized using flexural test analysis. Observation showed higher value of flexural strength for PMFC and PMFSC at 0.5% incorporation of MWCNTs. The flexural strength of sandwich PU foam is higher with an average value of 159.38% than control PU foam, due to Al sheet act as ductile skin and prevents samples from rupture rapidly. The modeling using finite element analysis (NX Software-version 8.5) showed the displacement nodal magnitude for 0.5% PMFC (2.537 mm) are higher than 0.5% PMFSC (0.288 mm).
Abstract: The effect of thermoplastic starch (TPS) and banana fiber contents on thermal characteristics of linear low-density polyethylene (LLDPE) matrix were investigated. The measurements from differential scanning calorimetric (DSC) and thermogravimetric analysis (TGA), proved the effectiveness of TPS and banana fiber in improving the blend degradation. On the other hand the LLDPE/TPS/banana fiber composites showed better thermal stability than the LLDPE/TPS blend, which is reflected to the LLDPE chains movement restriction. The incorporation of banana fiber into the LLDPE/TPS blends was found to interfere with the chains movement and resulting in more thermally stable and improving the blends stiffness.
Abstract: In this study, the dependence of gamma-ray absorption coefficient on amount and particle size of tungsten (W) in W-brass sintered compacts was investigated. To attain this goal, two sets of different W wt. % were prepared (W 65wt. %, W75wt. % and W85 wt. %). One set has compacts of as received powder and the other set has compacts of ball milled powder. The results showed that gamma-ray attenuation coefficient is inversely proportional to the particle size of the tested sintered compacts and directly proportional to the W content. Vickers microhardness, attenuation properties and microstructural characterization were carried out on the sintered samples. The attenuation test was conducted using gamma spectrometer with Genie 200 software. The samples of ball milled powder and of the highest volume fraction of W showed the highest hardness and attenuation values.
Abstract: The viability of metallocene linear low density polyethylene (mLLDPE) nanocomposites is being investigated as a new material for biomedical application. The effect of filler loadings on the ambient and in vitro (after being exposed in oxidizing condition, 37°C) mechanical properties was studied. We observed that, the mLLDPE nanocomposites have higher mechanical property values as compared to the neat mLLDPE. Furthermore, these properties were less affected by the in vitro conditions. The best ambient and in vitro mechanical properties were achived when 3wt% of organically modified MMT (organo-MMT) was added into the mLLDPE. It was postulated that the presence of MMT layered structure introduced a more tortous path for the diffusing of oxidant molecules, thereby decreasing their permeability towards mLLDPE molecular chains. The smaller amount of oxidants entering the molecular chains resulted in greater retention of mechanical properties when tested in vitro. This preliminary biostability studies show promising properties of the mLLDPE nanocomposite which possess the potential to be further developed for biomedical devices.
Abstract: Films of starch/PEO blends were prepared via solution casting technique and their properties with different amount of ammonium nitrate, NH4NO3 were compared. The measurement of conductivity at room temperature were carried out using impedance spectroscopy. The highest conductivity calculated is found to be 2.81±0.46 x 10-7Scm-1 with addition of 35wt% NH4NO3 .
Abstract: The chitosan filled thermoplastic elastomer (TPE) composites with different filler loading was prepared by melt mixing at 180 °C. The effect of 3-aminopropyltriethoxysilane (3-APE) as coupling agent on the rheological and thermal properties of composites were investigated. The melt flow indexer was used to characterize the melt flow index (MFI) of TPE/Chitosan composites at temperature of 180 to 210 °C. It was found that addition of chitosan into composites had reduced the MFI values. Besides that, the MFI values of composites were found to increase linearly with temperature. The treated composites demonstrated lower MFI values, indicated that better interfacial bonding was established between chitosan and TPE and the flowability of the composite melts was hindered. The TGA results reported that the treated composites had better thermal stability and lower total weight loss as compared to untreated composites at similar filler loading.
Abstract: All-cellulose composite using coconut shell powders (CSP) as natural lignocellulosic material and microcrystalline cellulose (MCC) were prepared by a surface selective dissolution. The effect of CSP content on tensile properties and crystallinity of CSP/MCC all-cellulose composites were investigated. It was found that the addition of CSP have increased the tensile strength and modulus of elasticity up to 3 wt% and decreased with further increment of CSP content. The elongation at break decreased with CSP content. The crystallinity of cellulose composites increased with the increasing of CSP content.
Abstract: The synthesis of polyethersulfone (PES)/polyvinyl acetate (PVAc) blend membrane was successfully developed by dry phase inversion method. The membrane morphology characterized using Field Emission Electron Microscope (FESEM) showed both polymers were homogeneously mixed and a dense structure was formed. A shift in characteristic peak for most chemical groups was observed in blend membrane as analyzed by Fourier Transform Infrared (FTIR) analysis which suggests the presence of molecular interaction between the blend polymers. The permeability of carbon dioxide (CO2) and methane (CH4) gases was recorded at a constant pressure of 10 bars and room temperature. The permeability across polymer blend membrane showed better performance as compared with native polymer membrane.